import java.util.Scanner;
class jisuan {
    int zhs(int m, int n) {
        if (m == 1) {
            return n;
        } else if (m == 0 || m == n) {
            return 1;
        } else if (m < n && m > 1 && n > 1) {
            return zhs(m - 1, n - 1) + zhs(m, n - 1);

        } else return -1;
    }
}
public class zuhe {
    public static void main(String[] args) {
        Scanner shuru = new Scanner(System.in);
        System.out.println("请输入m");
        int m=shuru.nextInt();
        System.out.println("请输入n");
        int n=shuru.nextInt();
        jisuan daan =new jisuan();
        if (daan.zhs(m,n)==-1){
            System.out.println("输入有误");
        }
        else
            System.out.println("C(m,n)="+daan.zhs(m,n));

    }

    }

